The proposed work is aimed at elucidating the role of chromophores in the photo-induced, cataractogenic crosslinking and aggregation of peptides in the lens. The principal technique used will be photoacoustic spectroscopy of whole and dissected cataractous lenses obtained subsequent to cataract removal surgery and normal lenses from donors. Spectra will be measured in the region from 200 to 2600 nm and compared to emission data from the same tissues. Samples will include lenses with brunescent, nuclear, nuclear-cortical and cortical cataracts as well as healthy normal lenses of as wide an age range as possible. The application of photoacoustic detection to the optical spectroscopy lens tissue avoids the inherrent problem of light scattering (especially in the opacified lens). This enables researchers to obtain the energies of absorption bands not previously obtainable by conventional transmission spectrosocpy of the whole cataractous lens.